Pneumatically powered hydraulic pump



March 4, 1952 J A. ROBERTS ET AL 2,588,164

PNEUMATICALLY POWERED HYDRAULIC PUMP 6 SheetsSheet 1 Filed April 7, 194a (gate s lNVi NA'lg RS 55/976 xr/ma 1?. 4750/58 MAECEL P 0 4 2 ATTO'RNEY March 4 1952 J. A. ROBERTS ET AL PNEUMATICALLY POWERED HYDRAULIC PUMP 6 Sheets-Sheet 2 Filed April 7, 1948 i 3 N2 5 La mm 3 5% w n m N 04 u r 2 d WW4 Y 4% a mm. mm ma pm 6 3 NM.

. P l w m .l R

March 4, 1952 J. ROBERTS ET AL, 2,588,164

PNEUMATICALLY POWERED HYDRAULIC PUMP Filed April 7, 1948 6 Sheets-Sheet 5 ATTORNEY March 4, 1952 J. A. ROBERTS ET AL 2,588,164

PNEUMATICALLY POWERED HYDRAULIC PUMP Filed April 7, 1948 6 Sheets-Sheet 4 TJIZ'IE.

TJHJE- MA/PCEZ AD'bhiM.

Patented Mar. 4, 1952 UNITED srAr s Pneumatic. Tool CompanygNew York, N. Y., a corporation of New Jersey .Applica'tion Aprili, 1948, Serial No. 19,478

16 Claims. (01. roe-:48)

l o, v This inventionrelates to pumps and more particularly to pumps which comprise a pneumatic and hydraulic combination.

In the smaller type industrial shops and especially in service garages ior motor vehicles, it is often required to have a high-pressure hydraulic source for such tools as power presses, rams, body and frame jacks, cylinder liner removers, as well as other hydraulic servicetools. It is usual for such shops and garages to maintain a live air line for various purposes, and the present pump has been adapted to operate with the usual pressure carried by such an air line. With an air line pressure of 90 pounds per square inch gauge, the pump willdeliver a hydraulic pressure of 8,006 pounds per square inch gauge. It. is a feature of the invention that-the control means are extremely versatile in that the hydraulic pressure delivered can be automatically maintained or released after pump operation has stopped. I

The prime object of this invention is to provide a new and novel pump which will furnish a high pressure hydraulic delivery when con-' nected to a low pressure pneumatic source.

Another object of this invention is to provide a pump which is simple to install and operate, has a variety of applications, has a versatile control arrangement, and is reliable under all service demands.

A further object of. this invention is ,to provide a Dump which has low initial and maintenance costs, is structurally compact, and of relative small size and low weight. These and further objects and features of the invention will become more apparent. when viewed in the light of the following specification and the accompanying drawings wherein: H

V 1 is a perspective view of a pump embodying the invention; f

Fig. 2 is an enlarged side elevation view of the pump; I I

Fig. 3 is an end view of the pump as seen from the throttle or back end in Fig. 2;. f

Fig 4 is a further enlarged longitudinal section ,of said pump, as indicated by the lines 4 in Figs. 9 and 10, with the parts in non-operative position;

Fig. 5 is a fragmentary'long'itudinal section, as indicated by the line 5-45 in Fig. .4, showing the oilreservoir bag maintained in spaced relation 75mm, s hou ing;

Fi 6 is an elevation ,view of apressure' r'e g'u later valve used in the pump, the figure being double size as compared-with Fig. 4;'

7 is'alongitudinal section taken along line l7 in Fig., 6

Fig. 8 is a cross-section indicated 8-8 of Fig. 4, but on a smaller scale," showing the oil reservoir. bag inflatedin full lines and partly collapsed in broken lines; v i

i Fig. 9 is a cross-sectional view of the pump as indicated by the irregular line 99 in Fig. 4," showing particularly the valvescontrolling the Fig. 10 a cross-sectional view of the pump lg. 15 is a ragmentary cross-sectional view in the sameplane as Fig. 9 but on double scale and showing thpressure regulator valve and distributor valve shifted, in response to the attainment of maximum -pressure, to automatically cut off the supply of live air to the cylinder;

Fig. 16 is across-section through the oil valve block, similar t e Fig. 10 but with a modified pressure relief valve of the manual or screw type;

Fig. 1' is an e evat onal view of the screw type valve usedin 16; Y,

v Fig. 18 is. a two-third size elevation view of an auxiliary reservoir system which is adapted to be connected by an air hose and an oil hose to the valve block of Fig. 10 or Fig. 16 a FigglQ isa full-size sectional view of a part of same taken alon ne "3-1. n 1 i 29; and A ,Fi 2o' is an end view of the part shown' in Fig. .19.-. {The pump is shown in Fig.) in operating position,,,it being understood, as will laterappear evident, that the pumpcan bereadily controlled by foot or.hand,}and will. operate satisfactorily inany position with regard to therelation oi the pump :axis to, the horizontal plane, any. par.-. ticular ;..operat i ng, set-up ,being in accordance with. the greatest convenience thereby, afforded, Thepneumatic and hydraulicportions are .indicated generally therein by the respective} morals ZflandZt (Figs l, 2 and Q Q An air, suprg ply line or hose 22 is connected to the pneumatic portion 28, while a high-pressure hydraulic delivery line or hose 23 is connected at one end to the hydraulic portion 2|, the other end of the hose 23 being connected to a hydraulically powered tool, such as a ram, not shown. The supply and delivery hoses 22 and 23 respectively are preferably of the flexible type to facilitate portage of the pump, as will be appreciated. The pump is designed to deliver a maximum hydraulic pressure of approximately 8,000 pounds per square inch gauge, when using a 90 pound per square inch gauge air supply. However, intermediate hydraulic pressures can be obtained, if desired, by proper throttle control, as will later be seen.

In constructing the pump advanta e has been taken of all known mechanical expedients to insure a maximum of eiliciency in its operation. In the specification, no specific mention is made ordinarily of elements such as piston rings. or seals, gaskets. and the like, but it should be understood that these elements are provided in the pump wherever necessary.

Pneumatic systemLive air supply Considering first the structure of the pneumatic portion 20 and referring to Figs. 2, 3, 4, 6, '1 and 9, the numeral 24 indicates a cylinder, bein most conveniently in the form of a casting, which is arranged to house and support the various elements reouired for the operation of the pneumatic cycle. The air hose 22 is connected to a standard inch pipe connection 25 which is screwed to the rear end wall of the cylinder 24, the conn ction 25 being provided with an air strainer 26 (Fig. 4) which is arranged to partially extend into a cavity 21, formed in the cylinder end wall. An air passageway 28 in the cylinder 24, leads upwards from the cavity 21 and into a throttle chamber 29 which is located at the top of the cylinder 24.

The throttle chamber 29 is cylindrical in form and has an axis which is generally parallel to the axis of the pump proper. One end of the throttle chamber 29 is sealed by means of a standard inch pipe plug 38, while at the opposite end, a bushing 3| is press-fitted into the chamber for a distance of a little less than one-half the overall length of the chamber.

A throttle valve 32 is slidably fitted in part within the bushing 3|, the forward portion of the throttle valve having a collar 33, which operatively serves to force a sealing ring 34 against a seat 35 formed on the inner or front end of the bushing 3|. Forwardly of the collar 33, the valve has a pilot portion 36 which serves to position a compression spring 31 located within the throttle chamber 29, and interposed between collar 33 and a pipe plug 30 which closes the front end of throttle chamber 29. The rear portion of the throttle valve 32 projects in part beyond the bushing 3|, the rear extremity of the valve being in contact at all times with a throttle lever 38, which is generally L-shaped, one leg of which is bifurcated and pivotally connected to the cylinder 24 by means of a pin 39, the other leg of the lever 38 extending in a direction over the throttle chamber 29 as shown. The throttle valve 32 has a reduced diameter mid-portion, which is of such length as to uncover ports 40 and 4| (Figs. 4, 9 and within the bushing 3|, during all positions of the throttle valve. An exhaust port 42 extends through the bushing 3| and cylinder 24, and is so positioned that it is uncovered by the reduced diameter mid-portion of the throttle valve 32, when said valve is in non-operative position, and is covered by the rear portion of the throttle valve, when said valve is in full operative position. An oil hole 43, extending through the cylinder 24 and bushing 3|, is provided for the convenient lubrication of the throttle valve 32.

It will now appear obvious that the throttling arrangement is such that when throttle lever 38 is fully depressed, the throttle valve 32 will be forced to a forward or full operative position, thereby covering exhaust port 42, unseating the ring 34, further compressing the spring 31, and thus allowing air in the throttle chamber 29 to pass around the reduced diameter mid-portion of the throttle valve, and enter simultaneously ports 40 and 4|. When the throttle lever 38 is released, spring 31 (assisted by the pressure of the live air) will force the throttle valve 32 to a backward or non-operative position, thereby seating the ring 34 to restrict further air passage from the throttle chamber 29, and will simultaneously uncover exhaust port 42 to allow exit to the atmosphere of air in passageways leading from ports 40 and 4|.

The port 48 opens into an air passageway 44 (Figs. 9 and 15) in the cylinder 24, said passageway extending forward to another section of the pump, the detailed description and function of which will be discussed later in the specification. The port 4| opens into an air passageway 45 (Figs. 4, 9 and 15) which passes downwardly in the cylinder and into a circumferential recess 46 formed on the outer surface of a valve bushing 41.

The valve bushing 41, which is best illustrated in Fig. 15, is cylindrical in form and is pressfitted within a transverse bore in the body of the cylinder 24, in the manner shown. The valve bushing 41 is open from end to end and has two smooth finished bores, a larger bore 48 and a smaller bore 49 which is concentric with and adjacent to bore 48. Both ends of the valve bushing 41 are internally threaded, the threads concentric with and adjacent to the larger bore 48 being adapted to receive a distributor valve stop 50, while the threads at the opposite end of the valve bushing are concentric with the smaller bore 49 and are adapted to receive a pressure regulator valve cap 5|.

Distributor valve Reciprocally positioned within the larger bore 48 is a distributor valve 52, which has a reduced external diameter mid-portion and is internally provided with a counterbore 53 and bore 54, both of which are smooth finished. Within the larger bore 53 of the distributor valve 52, is positioned a pressure regulator valve push pin 55, which has a narrow integral collar 56, slidably fitted to the bore 53. Also positioned in bore 53 is a distributor valve spring 51 which is maintained under compression, and which surrounds a major portion of the push pin 55, and is interposed be tween collar 58 and the bottom of the counterbore in the distributor valve 52. Beyond collar 58, the pin 55 has a pilot 58 for the positioning of a pressure regulator valve spring 59, maintained under compression and interposed between the collar 56 and a shoulder 68 in a bore 6| of the distributor valve stop 50. A hole 62 within the valve stop 58 is provided for open communication of the bore 6| with the atmosphere. The push pin 55 has a reduced diameter, at the end opposite the collar 56, which is arranged to slidably reciprocate within the bore 54 of the distributor valve 52. A shoulder 63 formed on the push 4.. r regulator a v ha a stem. rtion of cylindrical form reciprocably arranged in part within the bore 43 of the, valve bushing. 41 and projecting int evav tv 65. formed in the valve cap. til, the diameter of said cavit being. somewhat greater than the diameter of the ad-v jacent portion of the. valve 54. lifheopposite end of valve 64 abuts against distributor valve 52.. The regulator valve 64, best seen in Figs. 6, and 7, has a shoulder 65. (engageable with bushing 5,? to limit travel of the'valve in one, direction), and a circumferential. groove 5 which. connects. at two. points with a zig-jzag hole. arrangementfiii within the valve 64, the. function of said, groove 61 and hole arrangement 68 being. discussed, in, the operationof the pump as found later. in the. specification. h a h The distributor valve 52 and, regulator valve 64 are. shown in Fig. 9 in a non-operative position. In such position aiplurality of ports 69, radially positioned in the distributor valve bushing 4? allow for the passage of live airfrom the circumferential recess 46. to the bore 48 of the valve bushing 51, around the reduced diameter midportion of the distributor valve 52, through a plurality of radially arranged ports m in the valve bushing 41, into a circumferential recess ll formed on the outer surface of the valve bushing 41, and finally into an air passageway 12 which extends downwardly in the cylinder 24. However, when the distributor valve 52 and regulator valve 64 are shifted in the valve bushing 43 to the extreme left or operative position, i. e. when the distributor valve 52 is abutting the valve stop 58, as shown in Fig. 15, ports 69 are covered by the. distributor valve 52, and a plurality of ports .13 in the valve bushing 41 are placed in communication with the reduced diameter mid-portion of the distributor valve 52 as shown. Thus in the operative (Fig. 15) position, an air under pressure in passageway 12. will pass through recess H and ports 19, around the reduced. diameter mid-portion of the distributor valve 52 through ports '13, around a reduced diameter end portion. of the valve bushing 41, and out to the atmosphere. Itis to be notedthat a plurality of ports l4 radially disposed within the valve bushing 4?, are, uncovered by the distributor valve 52 when in operative position, the reason for which will be discussed in the operation of the pump, as found later in the specification. Summarizing, .the distributor valve 52 normally connects the passage: way 12 to live air, as shown in 9, untildisplaced by the pressure regulator valveBa, after which it connects passageway 12 to exhaust, as shown in Fig..15.

Shift valve The air passageway i2 exits into a shift valve chamber 75 (Figs. 4 and 9) which contains a shift valve 16 and a, shift valve. spring Tl maintained under compression; One end of the spring ii abuts against a pipe, plug 78, which closes the outerend of chamber l5, while the opposite end abuts against a shoulder on the shift valve iii. The shift valve l'fi has an elongated projection which is snugly fitted for reciprocation in ashift valve bushing l9; which is press-fitted. within the cylinder 2 3 at the inner end of the shift valve chamber 15. Forwardly of the, shoulder c t-shift valve 16 is a conical surface whichlat times seats against theend of;-the, shift valvebushin T3,

The shiftvalvebushing 19, has a rearwardly open counterbore which is somewhat largerthan the diameter of the shift valve elongated por-jection.

An air passageway opens into, the countcrbore,- 1 the function of said passageway being discussed,

shortly. The elongated. projection of; the. shift valve 15 projects beyond the end of the valve. bushing 79 into a mainairchamber 8;! in;

the. cylinder 24, andis. contact with a piston 82 during the. pumpnon-operative position, and

also during a part of the. movementof; the piston 32. t can be seen that when the pump is non-operative position, and while the shift valve 16. remains unseated by contact with the piston 82, egress of air from the shift valve. chamber 1-5 takes place along two paths, the. first of which is a continuation ofthe passageway 1.2: and which passes downwardly in the cylinder 24, the other path being around the elongatedporg'ection. of the shift valve 76, within the counterbore of the shift valve bushing 19, and then. through the passage. way 80. When the pump is in operative position, movement of the piston 82 permits seating of the. shift valve 16, due to the action of thev spring 11, cutting off flow of air through the passageway. 89, but allowing for. the flow of air through passageway 12. 7

u m tic va ve.

Passageway 12' leads into a circumferential; recess 83 (Fig. 9) formed: on the exterior surface of an automatic valve bushing 84', which is press-fitted to a cylindrical transverse. bore in the cylinder 26, as shown. A plurality of radi-- ally disposed ports 85, connect the recess 83 t0. the bore of the valve bushing 84, while recip: rocally arranged and snuglyfitted within the. valve bushing is an automatic valve. 86. Each end of the transverse bore. for the valve bush.- ing 84 hasa threaded portion which is adapted. to receive a valve bushing cap 811, each valve. bushing cap having a cavity which is concentricwith the automatic valve 86, and which has a diameter somewhat larger than the maximum diameter of the automatic valve 86. The automatic valve 86 has two reduced diameter portions 88 and 89, portion 88 being ofgreater length than portion 89,- whereas portion 89 has one end of ahole arrangement 90 which'provides an air passageway between portion 89 and the right extremity of the automatic valve 8J3, as seen n. e-.9.-

When the automatic valve 86 is inthe extreme s ter no r sra ve position, We svr cuits for air flow are established. In theflrst of the. two. circuits, the air in passageway '72 fi d ri c al. x t r u h ir mferen ial r cess d port 5, aro d redu ed, diame portion 89, and through the holes 951 of the au tomatic valve flffi, then through a passageway 91. (Figs. 4, 9 and 14). in. the cylinder 2.4, and for;

ward to cylinder port 92, in front of piston 82,

then out to theatm osphere, through ports 93,

the air in. the above described circuitalso finds egress through a small vent 9t.- -which, is; formed in the back wall of the cylinder 24, said vent being approximately in linewith. the passageway-9|, It is to.be.np ted that, the. pas.sage vay has, ewed, t vh h ven nio he main. air. chamber 8}, said. port 95 beingl cov -l ered. b he reri iie aiwel f th i ie 82.3 .1 ns. a ain: ar isan of: the. tr ke i h t me The uee ea tmt iav llz il ihet seu sei in the description or the pump operation which follows in the specification. I

In the second of the two circuits, any air in the main air chamber 8I finds exit through a passageway 96 (Figs. 9 and 14) which connects the main air chamber to the bore of the valve bushing 84, around the reduced mid-portion 88 of the automatic valve 86, through a plurality of radially disposed ports 91 in the valve bushing 84, to a circumferential recess 98 on the outer surface of the valve bushing 84, then on to the atmosphere through a series of ports 99 formed in the rear wall of the cylinder 24, the ports 99 best seen in Fig. 3. A small vent I (Figs. 3 and 9) connects the cavity in the left bushin cap 81 with the atmosphere, the purpose of which will be discussed in the operation of the pump, as found later in the specification.

A final detail in the structure of the pneumatic portion 20 of the pump concerns a short air passageway IOI (Figs. 4 and 15) which connects the main air chamber 8| and the cavity 65 of the regulator valve cap the function of the passageway IOI being discussed later in the specification.

Hydraulic system Considering now the structure of the hydraulic portion 2I and referring to Figs. 2, 4, 5, 8, and 10, the numeral I02 indicates a reservoir for housing an ail reservoir bag I03, which is made of a flexible material preferably a synthetic rubber, such as neoprene. The oil reservoir bag I03 contains oil and completely fills the reservoir I02 when the pump is in non-operative position, with the exception of a longitudinal region on the inside of the reservoir I02. wherein a fiat flexible strip I04 (Figs. 4 and 5) keeps the bag I03 away from the inner wall of the reservoir for the entire length of the strip I04. The strip I04 is riveted at one end to the wall of the reservoir I02 and is so arranged that the air passageway 44 exits into the space formed between the strip and the inner wall of the reservoir. In this manner the compressed air emerging from passageway 44 during pump operation, will act along the entire length of the oil reservoir bag I03 and thus avoid uneven collapse of the bag under pressure. In Fig. 8 the dashed lines represent a showing of a partially collapsed position of the oil bag I03.

The reservoir I02 is securely attached to an oil valve block I 05 (Fig. 4) by means of four screws I06 (Figs. 2 and 11), which pass through the block I05 and are arranged to also securely attach the cylinder 24 by flange means thereon, to the opposite side of the block I05. The air passageway 44 is arranged to pass through the oil valve block I05 so that an unrestricted path is provided for the fiow of air between those portions of the passageway 44 in the cylinder 24 and in the reservoir I02 respectively. The open end of the oil reservoir bag I03 is wedged between a tapered pilot I01 on the oil valve block I05 and a matched tapered surface on the inner end of the reservoir I02, so that a liquid tight seal is thereby efiected.

Hydraulic pressure release In the preferred embodiment the pump is so designed that the hydraulic pressure developed can be released simultaneously with release of the throttle "lever 38, by an automatic pressure release valve; or if desired, by a manipulative member after the throttle valve has been released, in case the operator decides to lock the automatic pressure release valve in closed position.

The numeral I08 indicates an automatic pressure release valve cylinder block which is securely attached to the top of the oil valve block I05 by means of two screws I09 (Fig. 10). An oil filler hole IIO, passes downwardly through the valve cylinder block I08 and continues into the oil valve block I05. A pipe plug III is screwed into the entrance to the oil filler hole H0 in the valve cylinder block I08. A threaded portion H2 is arranged at the mouth of the oil filler hole H0 in the oil valve block I05, to receive the plug III in the event that the automatic pressure release valve means is to be sub,- stituted by a screw type pressure release means, hereinafter described in connection with the modification of Fig. 16. An oil passageway H3 in the oil valve block I05, connects the oil filler hole IIO with the open end of the oil reservoir bag I03, as shown in Figs. 10 and 14.

An automatic pressure release valve piston H4 is positioned for reciprocal movement within the valve cylinder block I08. On the upper side of the piston H4 is formed a chamber II5 (Figs. 4 and 10), which is connected to the oil filler hole III! by means of an oil passageway II6 sloping downwardly in the valve cylinder block from the upper region of the chamber II5. It will be apparent that with such an oil passageway arrangement, the pneumatic pressure exerted on the oil in the oil reservoir bag I03 forces oil up into the chamber I I5, and the unit hydraulic pressure attained by the oil in the bag IE3, is transmitted to the upper surface of the piston II4. Projectable within the chamber I I5 is a pressure release valve block screw IIl, which can be rotated by means of a handle H8, for engagement with the piston I I4, in the event that the operator desires to prevent the automatic opening of the release valve.

On the under side of the piston H4 is a pressure release valve spring II9 (Figs. 4 and 10) maintained under compression at all times, and which is in abutting relationship with the under side of the piston I I4 through the intermediary of a washer I20, the opposite end of the spring being in abutment with the top surface of the oil valve bloc I05. concentrically positioned beneath the piston I I4 is a pressure release valve I2I, having the form of a cylindrical plunger, and which is adapted for reciprocal movement within a smooth finished bore I 22 extending downwardly in the oil block I05. The lower portion of the release valve I2I has a reduced diameter which terminates in a conical point. At the lower end of the bore I22, and surrounding a major portion of the reduced diameter of the release valve I2I, is a threaded portion I23 which is adapted to function in the event that the screw type pressure release valve is substituted as shown in Fig. 16. At the bottom of the bore I22, and concentrically arranged with the axis of the bore I22 and release valve I2I respectively, is a small oil passageway 24 (Figs. 4, l0 and 14) which extends downwardly within the oil valve block I05 and connects with a larger diameter longitudinal oil passageway I25. Another longitudinal oil passageway I26 connects the threaded portion I23 of the bore I22 to the open end of the oil reservoir bag I03, as illustrated in Figs. 4 and 10.

When the conical point of the pressure release valve I2I is seated in the opening of the passageway I24, the flow of oil from passageway I25 through passageway I 24,.about the reduced diameter portion ofv the valve I2I, through'the, passageway I26, to the oil reservoir bag I03, is prevented; and conversely, when the, pressurerelease valve is unseated, the flow of oil through said passageways i2; and I26 tothe; oil reservoir bag I03, is permitted, thereby providing a short circuit between the high and low pressurei ports of thehydraulic system for a purpose hereinafter setforth. Hydraulic pumping circuit u A short vertical oil passageway i2? (Fig. conects the longitudinal passageway II 3 to a chamber I28 formed in a bushing I29; which is positioned above a first check valve I30 (Figs. 1 0 and 14). The check valve I30 is adapted for reciprocable movement within a smooth finished vertical bore I3I formed in the oil valve block I05, the lower end of said bore opening on the bottom surface of the block I05. The check valve I30 is tubular in form, the top end being closed and having a beveled edge engageablewith a valve seat on the lower end of bushing I23 which functions to close the bottom of chamber I28. Within the check valve and extending therefrom, is a compression spring I32 which abuts agains't'an internal shoulder in the check valve I30 at the upper end, and-a check valve spring spacer I33 at the lower end. The spring spacer I33 is smoothly fitted to the bore I3I and is positionally maintained therein'by means of a pipe plug I 33, which is threadably afiixed at the lower end of said bore I3I. At th upper end of the check valve I30 is a plurality of ports I35 which are'radially disposed in the Wall of the check valve, the outside diameter of the check valve I 30 at the region of the ports I35 being somewhat less than the outside diameter of the lower portion of the check valve. Entering into the check valve bore I 3| and adjacent'the bottom edge of the bushing I29, is a transverse oil passageway I36.

Check valve I30 functions as an inlet valve'for the pump. It will be apparent that the operation of check valve I30 is mainly dependent upon the relativepressure of the oil in chamber I28 and passageway I 36. When the pressure of'the oil in chamber I28 acting against the top of the closed end of the check valve I30, is greater than the combined pressure of the oil in passageway,

E33 and the compressive pressure of the spring I 32 acting on the bottom of the closed end of check valve I30, the check valve will be unseated, and oil will flow from the chamber I28, around the recluceddiameter portion of check valve I30,;

to the passageway I35. Conversely, when the pressure of the oil in chamber I28 is less than the combined pressure of the oil ,inipassageway I36 and the compressive pressure of the ,spring I32, the check valve will be seatedand there will be no flow of oil between the chamber I28 and the passagewayfifi... Thepassageway I 36 leads through an oil pressurizing chamber I31 (Figs. 10and 14) which is cylindrical in form and which is concentrically arranged about the longitudinal axis of the pump, thence to a short passageway I33 which exits into a chamber I 39 formed in a bushing I40, which is positioned above a second check valve or discharge valve I4 I. Checl; valve I4 I is structurally like the check valve I30, and is reciprocably fitted to a smooth finished vertical bore I42 formed in the oil valve blockl05. Thelower end oi the bore l lt opens into the bottom surface oi the block I05 and is adapted to receive a pipe plug I 43, by-

2 ii q hh e h M at heio her e ii ere y; errie -tw e t he k l e I-fitihsl er er ed e i-the bus i s e... A en h ss P e-re blea nec the. he sr eeve ti h e1 s h esi n; di ghhthe bu h n M6;- Withr ene u in eqill assagewa 1 Theh tfi s W r-41. hea scamme -c t; I e e ion .q th n mies I4 3 is ca i M ss .s en a o m d, in he. side. tth q .r lre h hq ieloi aid. ca t .havihsa th ehde lne t hn an e t r c ive a 14?; Es a, l0 and. wh hi threadably connected the hydraulic delivery hose 23. i 1 t, 1 1 l It l he p e entthat W e t e nres ure he a t n on. t e l sed, hdoi11 h d va ve 1*" Within ch m er ift s g eat r h t e mmb n d re u Q t s n 1 and he ess rw h i in p sa e I a t ng; i h unde Side} of i osed hdJhe h eke a vedt wi e hs and O l i ..;fl W ro c ambe L3 ro nd he d c d, d m te of t e check al 141, th u op nin 5 nt rassasewa 1 5st cavity I46 and on to the hydraulically powered o .fino i howhk qhh ted to h rem eexmit o e. h st: 2 co ve sel wh n-t eta re cting 91 the filQ'etd hi t e check a ve '4' vW thin e c m er! 3 i ess th i h combined pressure of the spring I44 and the-pressure of the oil in passageway I25, the check valve I 4| will be seated and there will be no flow of oil between the chamber I39 and the hose 23. Thus,

the periodic lowering and raising of pressurein the oil pressurizing chamber I31 alternately draws oil from the reservoir bag I03, past the inlet check valve I30 into the pressurizing chamher; and then forces the oil, out of said chamber past the discharge check valve I4I to the delivery hose 23.

Pump apparatus x h On the side of the oil valve bloch lili opppsite h il re ir; ")2 s ahi h s ed ro ec L 3. {F s 4 d 5 Whi hi cq qeh ri allyt rah ed'-whh... tesh gt the. a is-oi thacy i r 2.4. he. mi 1. 15h!v a; ounterh em ,9, hich extends the entire 1 length of said projection and n inu t -the il rah? bla k 1% priaish r -w ee Whe e t meet a the e whi hc ormst P e ure hambe 1 1,. fi nc the diamet -re the ehet qr J larsentha t afliam te fth6h re h the re su iziha hamh al .1

. h h de I 411 othe hcl Qtsaid, sh I beis in eh tm t w he-h shin hu 35 1, w ich .1 rewed tge-thr ded portio t er i-reni it? as; hown- .i lheh shin -ihhas. .a c o ewh h i 0th fin shed roareqqe mp eme ttherein eta-p sto ram 3- Afpirc m shhM f .=-I 4., rm d in th ebprie t sh he. $l- CPQlln S he. n t nrami fi d z-h a e t c nect wit ass eway Wit-Wh h es. hro h he, b s n L 1; an

,r eii val h o kf t an exits int th to en of t 911 r s rvo r s;- I *Inth s m nne y Oil wh llrlfih l b h ihi hrehi t5 r lfi g pump operation finds ready passage back to the on s qir hr h i c i; 1. 1.1; f c; .191; z

Z Th iStQ eeIhitha ianheadsmr ienel5 5. which is maintained in abutting relationship with I around the base of the projection I48.

- strength of spring I51 is sufiicient'to fully retract 1 1' the piston 82 by means of a compression spring I51, through the intermediary of a piston ram washer I58, the opposite end of the spring I51 abutting against the wall of the oil valve block The the piston 82 when the air in the main air chamber 8| is exhausted to the atmosphere.

The length of the piston ram I53 is such that when the piston 82 is in non-operative position, the end of the ram within the oil valve block I05 is approximately in line with the shoulder I50, as shown in Fig. 4. The diameter of the piston ram I53 is approximately two-thirds the diameter of the pressurizing chamber I31. The forward end of the pressurizing chamber I31 is closed by a pipe plug I59 which provides a liquid tight seal for that end of the pressurizing chamber I31.

On the side of the piston 82 within the main air chamber 8| is a cylindrical projection I60 arranged concentrically with the pump axis, said projection I60 serving to limit the extreme backward movement of piston 02, as is clearly evident in Fig. 4. A piston ram seal I8I, made of a flexible material such as leather for example, surrounds the projection I60 and slidingly engages the walls of the cylinder 24, serving to provide a sealing means for the air in the main air chamber 8|. The seal I6I is positionally maintained by means of a washer I02 and a retaining ring I83, which is fitted to the projection I60, as shown.

Operation Before entering into a description of the operation of the pump, it is desired to point out certain features or expedients which are embodied in the structure of the pump, some of which may not have appeared obvious.

First, the length of the pressurizing chamber I31 is such-that the end of the piston ram I53 is free from contact with the closed end of said pressurizing chamber, 1. e. the plug I59, when the piston 82 has moved to the extreme limit of its working stroke.

Second, the quantity of oil in the pump hydraulic system at the completion of an operating cycle i. e., after the oil has returned to the reservoir, is the same as the quantity of oil in the pump hydraulic system before the start of an operating cycle, excepting of course, that which may be lost due to any leakage. This is arranged by the use of a check valve hose coupling, not shown, of the type having a spring seated valve which is unseated or opened only when the coupling is connected. The male portion of the coupling is attached to the end of the hydraulic hose 23, while the female portion is attached to the hydraulically operated tool. Thus when the coupling is connected, the pump forces oil from the hose 23 past the open check valve hose coupling and into the hydraulically operated tool connected thereto, whereas the return stroke movement of the hydraulically operated tool forces the oil past the check valve hose coupling into the hose 23 and back to the pump reservoir proper. The use of a check valve hose coupling of such type, provides for ready make-and-break connection of the pump to whatever type of hydraulically operated tool it is desired to use at the time, and still prevents the oil from draining from the hose 23 when the hose is not attached to a tool.

Third, regarding the capacity or output of the pump, it is obvious that such is merely a matter of proportion of the various pump parts. However, for a commercial embodiment of this in- 12 vention, an oil delivery fiow of 38 cubic inches per minute at 8,000 pounds per square inch is attained from an oil reservoir capacity of 45 cubic inches. To augment the oil capacity of a pump of any given size, the use of an auxiliary reservoir as later described and illustrated in the drawings, may be provided.

Fourth, it is to be noted that the pump is supported for normal upright position by means of flat portions on the bottom of the cylinder 24, oil valve block I05 and oil reservoir I02, as best seen in Fig. 2. However, as has been mentioned heretofore, the pump will operate satisfactorily while maintained in any desired position.

Finally, in accordance with the usual construction of machines in this general class, an air line oiler of any suitable type may be provided in order that a small amount of oil may be introduced into the live air as a lubricant for the valves and the air operated piston.

Turning now to a consideration of the operating cycle of the pump, Figs. 4, 9 and 10 illustrate the relative position of the various movable parts of the pump when the pump is in nonoperative position. Since the foregoing description of the pumps structure has been made with reference particularly to the pump in non operative position, it is not deemed necessary to again discuss the relative position of the movable parts of the pump when in non-operative position. If the operator desires that the hydraulic pressure developed by the pump and delivered to the hydraulically operated tool, is to be automatically released after the throttle lever 38 is released, he merely observes that the handle II8 (Fig. 4) has been rotated so that the release valve screw H1 is free from contact with the release valve piston II4; whereas, if he wishes the developed hydraulic pressure to be maintained after the throttle lever is released, he checks to see that the handle I I8 is rotated so that the release valve screw I I1 is in contact with the piston II4.

Assuming then that the pump is connected to a source of live air by means of the air hose 22, and the delivery hose 23 is connected to a hydraulically operated tool, and that the automatic release valve is set for automatic release (as in Fig. 4), the operator initiates the pump operating cycle by fully depressing the throttle lever 38. The throttle valve 32 is thereby unseated and live air flows from the throttle valve chamber 29, past the valve seat 35, about the reduced diameter of the throttle valve 32 and into ports 40 and 4|. The air entering port 40 passes through the air passageway 44, enters the air reservoir I02 and acts upon the exterior of the oil bag I03, thereby pressurizing the oil contained therein and forcing oil into the oil passageway II3, from which it passes into oil passageways IIS and I21 (Fig. 10). The oil in passageway IIB flows upward into the chamber H5, and acts upon the piston 4, which results in the seating of the pressure release valve |2I in the opening of the passageway I24. The oil in passageway I21 enters the chamber I28, Where the pressure of said oil unseats the inlet check valve I30, the oil thereby advancing through passageway I36 into the pressurizing chamber I31, wherein it is eventually pressurized by the advance of the piston ram I53.

The air going through port 4| (Fig. 9) passes through passageway 45 and ports 69 into the bore of the valve bushing 41, about the reduced diameter mid-portion of the distributor valve 52,

and through the radial ports-'10 and annular-recess 'II- totheair passageway l2, 'I'heair-f-rom passageway 12 enters the shift valvechamber-l5 (Fig; 4), some ofthe air passing onward'through said chamber and into the continuation of passageway 12-, while some flows past the unseated shift valve 16 into the passageway 80. The air in passagewayfiil enters the cavity-in the left cap 87 (Fig. 9), thereby shifting the automatic valve 86 to the right, where the end of the valve 8t abuts against the bottom of: the cavity formed in the other cap 87. The automatic valve- 86in shifting to the right, uncovers the vent I- so thatair in the cavity of the left cap 8'3 is'eX- hausted to the atmosphere. I

The air which flows downward fromthe shift valve chamber 15 through the continuation of passageway 72 (Fig. 9), is allowed to exhaust to the atmosphere before the automatic-valve 85 is shifted to the right, such exhaustingtaking place by way of annular groove 83, bushing ports 85;valve recess 89, passageways 953 in the automatic valve 86 and through the passageway 9| (Figs. 4 and 11), port 92, andthen through cylinder exhaust ports 93. After the automatic valve 8I5-is shifted to the right, the air from passageway flows about the reduced diameter portion 8230f the automatic valve 86, into passageway 96 (Figs. 9, 11 and 14), from where it enters the main air chamber 8|. As the air builds up-pressure in the main air chamber 8!, piston 82 begins to move, which results in the compression of the spring ll-and the simultaneous pressurizing of the oil in chamber I31 by means of the advance therein of the piston ram I53. continues its movement which constitutes the power stroke, contact with the shift valve '56 is released and ended, as the shift valve 16 is allowed to seat by action of the spring Tl, thereby cutting off the flow of air from chamber 75 to the passageway 80.

Power stroke Fig. 11 illustrates the firststage in the power:

stroke of the pump, as just discusssed. The single-headed arrows indicate air at no greater than air line pressure, the double-headed arrows indicate oil under air line pressure, and the tripleheaded arrows indicate oil under higher pressure As the piston seated, each as a result of the pressurization of the oil in the pressurizing chamber I37, andthat' the oil is flowing under pressure into the oil delivery hose 23. As has been indicated in the preceding discussion of the pumps structure, the

compression springs I32 and M4 of the check valves I30 and MI respectively, provided for the automatic actuation of the said valves in accordance with the relative pressure of the oil in the pressurizing chamber I31 and the oil in the oil bag I03.

It may be pointed out that the maximum pump delivery pressure of 8,009 pounds per square inch is not ordinarily realized after the completion of the first power stroke, but rather is attained only after a series of successive power strokes, in accordance with the amount of oil that will have to be pumped to the hydraulic tool which is connected to. the pump. In other words, some tools mayrequire full oil capacity of the pump before which case the piston 82 will undergo a certain number of reciprocations to pump the required amount ofoil, and hence the maximum. oilpressure of 8,000 pounds. per square inch: will be may be run out at full speedzorit canbe inched forward, stopped, held'in position, or retracted, as desired.

- Return stroke Fig. 12 illustrate the, relative position of the variousparts of thepump just after completion of-a power stroke and at the beginning of the return stroke. It will be seen that when the piston 82 is advancedduring the power stroke to acertain position, which can be termed maximum forward position, cylinder port 95 is uncovered and port 92 is simultaneously covered by the piston head, thereby allowing air in the main air chamber SI to flow through port 95 into passageway 9I, to the reduced diameter mid-portion 89v of the automatic valve 86, and into hole arrangement within said automatic valve. The air which exists from the hole arrangement 99, builds 'uppressure behind the right end of automatic valve 86 within the cap 8?, and forces the automatic valve to the left, i. e. the end being forced into abutment with the bottom of the cavity in the'other cap 81. Upon movement to the left the valve se displaces the air in left cap 8'! which escapes-to atmosphere around theperiphery of valve 36 and through the small port It?!) (Fig; 9) Thev shift of valve 35 to the left places the passageway 96 (Figs. 9 and 12) in communication with the ports 99 by way of the reduced diameter portion 88 of the automatic valve 86, thereby exhausting the air in the main air chamber 8i to the atmosphere. As soon as the pressure in the main air chamber is released, the spring I5! acts to force the piston 82 rearward to its initial position within the cylinder 24. It is to benoted that the. port is uncovered only for that instant during which the piston 82 is in maximum forward position, and that some of the air in passageway i2 is bled to the atmosphere during the return stroke of the piston via the hole arrangement 90, passageway 9!, ports 92 and 93, and also restricted vent 94.

During the return stroke of the piston, the pres- )surizing chamber I3! expands in size to reduce the. pressure on the oil therein, while the air in passageway 44 is still acting upon theoil bag I03, thereby forcing a slug of oil past the inlet check valve I30 and into the pressurizingchamber- I31, in preparation for the next pressurizing. stroke of Distonram I53.

As the piston 82 repeatedlyv reciprocates, the oil pressure gradually rises in the discharge hose '23, causing a corresponding rise in the resistance of discharge valve I4I to opening movement and in the resistance offered by the oil in pressurizing chamber I31 to forward movement of the piston ram I53. Against this increased opposition the forward motion of the piston a2 becomes less rapid as compared with preceding strokes. Under ordinary operating conditions, however, the opposition is still small enough, and theforward travel of the piston still fast enough, to prevent the air in cylinder chamber 8I from approaching line pressure (say 90 p. s. i.) as the chamber ex pands on the power stroke. Accordingly the pressure regulator valve 64 and distributor valve 52 remain in the non-operated position of Fig. 9 under normal operation.

Oil pressure release It has been pointed out that the piston 82 starts to reciprocate when the throttle lever 38' is depressed and continues in a succession of pumping strokes until the throttle lever is released. When this occurs, the oil pressure in hose 23 may not be automatically released, depending upon the setting of the manipulative screw II1. If the screw (Fig. 4) is forced down on pressure release valve piston II4, the pressure in hose 23 will be maintained because the oil in that hose has no means of escape back to the oil reservoir bag I93.

If, on the other hand, the operator desires to have the oil released from hose 23 automatically upon closing of the throttle, he first conditions the machine for automatic pressure release by withdrawing the screw I I1 out of the path of the pressure release piston I I4. When operating with such a setting the valve piston H4 is held down by the pressure of oil admitted through passage I I6, which is maintained only so long as live air is delivered through the throttle valve and passage 44. When such pressure is released the pressure release valve I2I rises under the infiuence of spring IIS to open a path from the oil hose' 23 direct to the reservoir bag I03, independently of the check valves, as above described.

Manual pressure release In the modification of Fig. 16 the automatic pressure release valve piston H4, and its associated housing, spring, etc., are omitted to simplify the structure and reduce the manufacturing cost. Instead of the automatic valve I2I, the modification comprises a manual valve I2 Ia (Figs. 16, 17) having a threaded portion I2Ib engageable with the screw threads I23 in the oil valve block I05. Seating and unseating of the modified pressure release valve I2 la is effected by turning the handle I2Ic. In other respects the valve I2Ia is comparable to the automatic valve I2 I. In the modification of Fig. 16, the threaded opening I I2 is directly engaged by a pipe plug for closing its upper end.

Pressureregulator In the foregoing discussion it was assumed that the operator would release the throttle lever and stop the pumping operation before the pressure in oil hose 23 attained a dangerous value. If he fails to release in time, however, the pressure regulator automatically comes into operation and stops the reciprocations of the piston, without however, releasing the pressure of the oil already pumped into the hose.

Figs. 13 and 14 illustrate the relative position of the various parts of the pump just at the time that maximum pump pressure is reached. Assuming that the maximum oil pressure of the pump under discussion is 8,000 pounds per square inch, then the effective air pressure in the main air chamber 8| will not realize a maximum value until the maximum oil pressure is realized in the pressurizing chamber I31. When this occurs, the piston 82 is short stroked and the air in the main air chamber 8I has time to build up and approach line pressure, and by way of passageway IIII, to force the regulator valve 64 toward the left in the valve bushing 41, which results in the simultaneous shifting to the left of the distributor valve 52,

so that the end of said valve 52 abuts the distributor valve stop 50, as shown in Fig. 15. In such a position, the distributor valve 52 allows exit to the atmosphere of the air in the main air chamber 8|, by way of passageway 96, about the portion 88 of the automatic valve 86, through passageway 12 and onward about the reduced diameter midportion of the distributor valve 52, and finally through ports 13 in the bushing 41.

When the distributor valve 52 is in its shifted position (Fig. 15), the ports 69 are covered by the distributor valve, while the ports 14 are uncovered. This allows the live air from passageway 45 to act upon the end of the distributor valve 52 which is in abutment with the regulator valve 64, and to hold the distributor valve in shifted position independently of the pressure exerted upon the distributor valve by the regulator valve 64. Under these conditions the distributor valve 52 may be released from shifted position, only upon release of the throttle lever 36, which results in the cutting off of air fiow to passageway 45, and allows escape of air from passageway 45 to the atmosphere by means of port 42, thus permitting the regulator valve spring 59 to shift the distributor valve 52 to its first or normal position. The strength of the regulator valve spring 59 is a factor which determines the point of cut-off for the hydraulic delivery pressure, it being obvious that a spring with a lower compression factor will allow the distributor valve 52 to be shifted at a lower value of hydraulic delivery pressure, which is directly refiected in the pressure of air in the main air chamber 8 I. It will be seen that the zig-zag hole arrangement I58 of the regulator valve 64, prevents the trapping of air within the chamber formed in the valve bushing 41 at the end of the distributor valve 52, and thus allows the unrestricted seating of said distributor valve.

Auxiliary reservoir While it is apparent that the oil capacity of any given pump of the present type is constant once the dimensions of the parts are established, extra oil capacity can be obtained by means of an auxiliary oil reservoir, which is readily connected to the pump, for use of the pump with hydraulic tools requiring more oil capacity for operation than that normally afforded by the pump. Figs. 18, 19 and 20 illustrate an auxiliary reservoir system, which when connected to the pump, increases the oil capacity by approximately three times. In identifying parts of the auxiliary reservoir system, numerals which have been previously used in the detailed description of the pump will be reused, with the letter "a following, to identify identical or corresponding parts.

The auxiliary reservoir system is simple in structure and basically consists of three main parts, a connection block I64 and two reservoir portions I62a, each containing an oil reservoir bag I03a. The reservoir portions I02a are connected to the block I64 on opposite sides thereof by means of four bolts I06. A tapered pilot III1a is located on opposite sides of the block I64, the purpose of said pilots being for centering the reservoirs I02a with respect to the block I64, and also for fixing the reservoir bags IBM in liquid tight manner. Extending into the block I64 from one face are two bores I65 and I66, each having a threaded portion at the entrance thereof. Passageways I61, leading from the bore I65 at two points, exit on each side of said block I64 in a region near the base of each pilot Illla, each of said passageways I61 being located in line with the opening of passageway 44a in the reservoir portion IBM. The bore I 66 has passageways I 66 leading therefrom at two points, and opening on the surface of each pilot Iilla in the region of the open end of the oil bag Iota. A transverse passageway 169 having a diameter approximately equal to the diameter of the bore I66, extends through the block E65, and connects the bore I66 to the surface of each pilot iilla, the ends of said passageway I63 also being in the region of the open end of the oil bag 33a.

The auxiliary reservoir system is connected to the pump by means of two pipes, not shown, but represented diagrammatically by the broken lines and A respectively. The first end of pipe 0 is threadably connected by means of standard pipe connections to the bore I 66 in block I64 (Fig. 20), the second end of said pipe 0 being threadably connected to the oil filler hole H0 in the oil valve block I65 (Fig. 10); or alternatively to threaded opening H2 in Fig. 16. In similar manner the first end of the other pipe A is connected to the bore 65 in the block I64 (Fig. 20), the second end of said pipe A being connected to a threaded bore Ill] (Fig. 10), which is formed in the oil valve block M5; or alternatively to a threaded bore IIIJa (Fig. 16). The bore I 70 (or Ilfla) is connected to the oil pas sageway 45 by means of a passageway I'll (or Illa). When the pump is not connected to an auxiliary reservoir system, as set forth above, the oil filler hole H0 and the bore H0 are plugged by means of standard pipe plugs Ill.

The operation of the auxiliary reservoir system and the manner in which it functions to supplement the oil capacity of the pump is as follows: Some of the air in passageway 4 enters passageway Ill and bore- I in the oil valve block I05, then passes through the interconnecting pipe A to the bore I65 and through passageways I6I in the block I64, and exits into each oil reservoir I020: to exert pressure upon the oil in the oil bag I03a, contained therein. As a result of the pressure on the oil bag I63a, oil is forced out of each oil bag I03a into passageways I68, and bore I66 in the block I64, through the interconnecting pipe 0 and into the hole filler hole H0 in the oil valve block I05, the oil thus becoming part of the oil system of the pump.

A divisional application, Serial No. 252,762, filed October 16, 1951, contains claims relating to an auxiliary reservoir system, and to an air motor per se, all as shown and described herein.

What is claimed is:

1. A pump comprising in combination a pneumatic portion, a hydraulic portion coupled to the pneumatic portion, and a reciprocable piston contained in part within each of said portions, said pneumatic portion being arranged to receive a pneumatic medium and having a passageway arrangement which directs an amount of said medium for motivation of said piston and another amount to the hydraulic portion, said hydraulic portion having an oil reservoir the volume of which can be decreased by action of said pneumatic medium, a check valve system including a liquid pressurization chamber, an oil delivery outlet located at the exterior of the pump, and connecting said outlet with said reservoir means forming a liquid return flow passageway, said check valve system being interposed between the reservoir and the outlet and further positioned so that a. portion of the piston extends into the pressurization chamber, all

18 arrangedso that liquid is forced from said res ervoir by action of the pneumatic medium, passes through the check valve system while being pressurized by action of the piston within the pressurization chamber, is delivered to the outlet under increased pressure, and is returned to the reservoir by the return flow passageway after pressurization ceases.

2. A pump comprising in combination a pneumatic portion, a hydraulic portion coupled to the pneumatic portion, and a reciprocable piston contained in part within each of said portions and being movable in one direction by pneumatic pressure and in the opposite direction by mechanical means, said pneumatic portion being arranged to receive a pneumatic medium and having a pressure responsive valve system which automatically directs a given quantity of said medium for motivation of said piston, said hydraulic portion having an oil reservoir which is collapsible under action of pneumatic medium received from the pneumatic portion, a check valve system including a liquid pressurization chamber, an oil delivery outlet located at the exterior of the pump, and connecting said outlet with said reservoir means forming an oil return flow passageway, said check valve system being interposed between the reservoir and the outlet and further positioned so that a portion of the piston extends into the pressurization chamber, said hydraulic portion being arranged so that oil is forced from the reservoir by pneumatic pressure through a first part of said check valve system, thereafter through said pressurization chamber where the oil is pressurized by reciprocable action of said piston, and through a second part of said check valve system to the oil delivery outlet, and is returned to the reservoir by the return flow passageway after the oil pressurization is stopped.

3. A pump according to claim 2, wherein said piston movement mechanical means comprises a pro-compressed spring.

4. A pump according to claim 3 wherein said pneumatic portion has a throttle means operable to initiate the operating cycle of said pump.

5. A pump according to claim 4 wherein an oil delivery pressure release means is included in the oil return fiow passageway.

6. A pump according to claim 5 wherein said pneumatic portion has a valve which automatically releases to the atmosphere the pressure medium acting upon the piston when the oil in the pressurization chamber has been pressurized a predetermined amount.

'7 A pump according to claim 6 having means adapted for the reception of an auxiliary reservoir system which automatically operates to supplement the oil delivery capacity of the pump, said auxiliary reservoir system including one or more oil reservoirs which are collapsible under action of pneumatic medium delivered by hose means from the pump to thereby force oil from the reservoirs through hose means to the hydraulic portion of the pump.

8. In a pump of the character described, a hydraulic portion comprising a reservoir having a bag containing a liquid medium, said reservoir being arranged for the collapse of said bag by pneumatic pressure; a valve block connected to said reservoir and containing in part a reciprocable piston means, a first chamber having a first check valve, a first passageway connecting said first chamber to an open end of said bag, a pressurizing chamber being arranged for the 1 Q pressurization of liquid therein by action of said piston means, a second passageway connecting said pressurizing chamber to said first chamber, a second chamber having a second check valve, a third passageway connecting said second chamber to said pressurizing chamber, a liquid outlet means, a fourth passageway at one point connecting said liquid outlet means to said second chamber, a third chamber having a pressure release valve reciprocably arranged therein, and a fifth i passageway connectin said third chamber to an open end of said bag, said third chamber being also connected to another point of said fourth passageway, said first check valve being resiliently maintainable in a first position to prevent passage of liquid from said first passageway into said second passageway and being hydraulically maintainable in a second position to allow passage of liquid from said first passageway into said second passageway, said second check valve being resiliently maintainable in a first position to prevent passage of liquid from said third passageway into said fourth passageway and being hydraulically maintainable in a second position to allow passage of liquid from said third passageway into said fourth passageway, said pressure release valve being maintainable in a first position to prevent passage of liquid from said fourth passageway into said fifth passageway and being maintainable in a second position to allow passage of liquid from said fourth passageway into said fifth passageway.

9. In a pump hydraulic portion according to claim 8, automatic means for positioning said pressure release valve in said first and second positions comprising a piston having a top surface forming a wall of a chamber which is connected to the first passageway in said valve block and a bottom surface which abuts one end of said pressure release valve, and a resilient means in abutment with the bottom surface of said piston, all so arranged that a liquid under pressure fiowing from said first passageway into said chamber urges said piston in a direction to force said pressure release valve into said first position, while when said liquid is caused to flow from said chamber into said first passageway said resilient means urges said piston in a direction to allow movement of said pressure release valve into said second position.

of said piston, said member being manually adjustable to restrict movement of said piston to an extent that said pressure release valve is maintained in said first position.

11. In a fluid pressure operated hydraulic pump including a motor end and a pump end, a cylinder in the motor end providing a piston chamber, a piston reciprocating therein, means in the motor end including a throttle valve for supplying live air to the piston chamber to effect such reciprocations, a valve block attached to the cylinder for closing an open end of the piston chamber, an oil reservoir attached to the opposite side of the valve block, a high pressure outlet on said block, a piston extension of reduced diameter projecting forwardly into the valve block, said block having a pressurizing chamber receiving the piston extension, said valve block having two separate passageways between the reservoir and the outlet, one passageway leading from the reservoir through an inlet check valve to the pressurizing chamber thence through a discharge check valve to the outlet, the other passageway extending from the outlet through a pressur relief valve back to the reservoir.

12. In a fluid pressure operated pump according to claim 11 an arrangement whereby the pressure relief valve is adapted to be closed when the throttle valve is open and to be opened when the throttle valve is closed, whereby the operator may discontinue the pumping operation and release the oil pressure at the same time.

13. In a fiuid pressure operated pump accordin to claim 11, an arrangement whereby the throttle valve supplies live air to close the pressure relief valve only as long as the throttle valve is open and also supplies air to the reservoir for forcing the oil into the pressurizing chamber during the rearward stroke of the piston.

14. In a fluid pressure operated hydraulic pump according to claim 11 an arrangement whereby a pressure regulator valve is adapted to cut off the flow of live air from the throttle valve to the piston chamber upon development of a predetermined opposition to the forward stroke of the piston.

15. A pump pneumatically operable to pressurize a hydraulic medium within the pump for delivery to a device served by the pump, the pump being arranged for the return of said medium for storage when in non-operative condition comprising, a pneumatic portion including valve means and a piston chamber, a hydraulic portion connected to the pneumatic portion, and a piston contained in part within each of said portions and pneumatically movable to pressurize hydraulic medium entrapped in a pressurizing chamber formed in the hydraulic portion and movable in the opposite direction by resilient means, said pneumatic portion having a pneumatic inlet means and passageways leading therefrom to conduct pneumatic medium to the exterior of a collapsible reservoir located within the hydraulic portion and containing hydraulic medium and to the valve means, said valve means arranged to admit pneumatic medium to the piston chamber containin part of the piston whereby the piston is moved to pressurize the hydraulic medium and further arranged to release pneumatic medium from the piston chamber so that the piston can be moved by the resilient means, said valve means including a pressure regulating valve which cuts ofi delivery of pneumatic medium to the piston chamber when a predetermined hydraulic pressurization is realized, said hydraulic portion including a hydraulic medium delivery means and valves to maintain pressurized hydraulic medium within the delivery means and further to allow return of the hydraulic medium to the reservoir when the pump is in non-operative condition.

16. A pump comprising a pneumatic portion in cluding a main chamber and pneumatic valve means, a hydraulic portion coupled to the pneumatic portion and including an oil reservoir, an oil pressurizing chamber, an oil outlet, and check valve means, piston means slidably arranged in the main chamber and including a ram which extends into the pressurizing chamber, a passageway arrangement for conducting pneumatic medium to the pneumatic valve means and to the oil reservoir, said hydraulic portion having a passageway connecting the reservoir to the pressurizing chamber via a check valve and a passageway connecting the pressurizing chamber to the oil outlet via a check valve, said check valves arranged for the one way flow of oil from the reservoir, through the pressurizing chamber and to the oil outlet, oil hose delivery means connected to the oil outlet for attachment to a device served by the pump, said pneumatic valve means adapted to automatically admit pneumatic medium to the main chamber to move the piston means whereby oil is forced from the pressurizing chamber under increased pressure, and further adapted to out 01f flow of pneumatic medium to the main chamber when the pressurization of oil attains a predetermined value, and oil pressure valve means in the hydraulic portion arranged to maintain oil pressure in the oil hose delivery means after cessation of piston movement and further arranged to release the oil pressure and allow return of oil to the reservoir when the pump is in non-operative condition.

JAMES A. ROBERTS.

HOWARD R. FISCHER.

MARCEL P. D'HAEM.

22 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Datev 1,485,138 Johnson Feb. 26, 1924 1,743,968 Hatfield Jan. 14, 1930 2,001,190 Ginter May 14, 1935 2,042,744 Tear et a1 June 2, 1936 2,080,695 Cargile May 18, 1937 2,134,734 Reinhold Nov. 1, 1938 2,324,701 Herman July 20, 1943 2,347,379 Teeter Apr. 25, 1944 2,406,747 Davis Sept. 3, 1946 2,433,759 Hess Dec. 30, 1947 

